Étude des isotones N = 81 : 139Ce, 141Nd, 143Sm, au moyen des réactions (d, t ) et (3He, α)

Les niveaux excités des isotones N = 81 : 139Ce, 141Nd, 143Sm, ont été étudiés au Tandem MP d'Orsay jusqu'à plus de 3 MeV d'énergie d'excitation, essentiellement au moyen d'un spectromètre magnétique split pole, en utilisant les réactions (d, t) à 26,21 MeV (resolution :14 keV) et (3He, α) à 25 MeV (résolution : 23 keV). Les distributions angulaires correspondant à un grand nombre de niveaux finaux (~ 90 pour les 3 isotones) ont été analysées en approximation de Born avec ondes distordues (DWBA). Beaucoup des niveaux analysés (plus de 30) n'avaient pas été observés ou séparés dans les expériences (p, d) ou (d, t) antérieures. La force à une particule est généralement répartie sur plusieurs niveaux, la fragmentation étant particulièrement importante pour les sous-couches 2d 5/2 et 1g 7/2. Des calculs tenant compte du couplage des états à un trou avec les états collectifs du cœur, effectués par Heyde et Brussaard, reproduisent convenablement la partie de basse énergie d'excitation des spectres expérimentaux, mais ne reproduisent pas la fragmentation observée à énergie d'excitation plus élevée

Digitised audio questionnaire for assessment of informed consent comprehension in a low-literacy African research population: development and psychometric evaluation.

OBJECTIVE: To develop and psychometrically evaluate an audio digitised tool for assessment of comprehension of informed consent among low-literacy Gambian research participants. SETTING: We conducted this study in the Gambia where a high illiteracy rate and absence of standardised writing formats of local languages pose major challenges for research participants to comprehend consent information. We developed a 34-item questionnaire to assess participants' comprehension of key elements of informed consent. The questionnaire was face validated and content validated by experienced researchers. To bypass the challenge of a lack of standardised writing formats, we audiorecorded the questionnaire in three major Gambian languages: Mandinka, Wolof and Fula. The questionnaire was further developed into an audio computer-assisted interview format. PARTICIPANTS: The digitised questionnaire was administered to 250 participants enrolled in two clinical trials in the urban and rural areas of the Gambia. One week after first administration, the questionnaire was readministered to half of the participants who were randomly selected. Participants were eligible if enrolled in the parent trials and could speak any of the three major Gambian languages. OUTCOME MEASURE: The primary outcome measure was reliability and validity of the questionnaire. RESULTS: Item reduction by factor analysis showed that 21 of the question items have strong factor loadings. These were retained along with five other items which were fundamental components of informed consent. The 26-item questionnaire has high internal consistency with a Cronbach's α of 0.73-0.79 and an intraclass correlation coefficient of 0.94 (95% CI 0.923 to 0.954). Hypotheses testing also showed that the questionnaire has a positive correlation with a similar questionnaire and discriminates between participants with and without education. CONCLUSIONS: We have developed a reliable and valid measure of comprehension of informed consent information for the Gambian context, which might be easily adapted to similar settings. This is a major step towards engendering comprehension of informed consent information among low-literacy participants

A multimedia consent tool for research participants in the Gambia: a randomized controlled trial.

OBJECTIVE: To assess the effectiveness of a multimedia informed consent tool for adults participating in a clinical trial in the Gambia. METHODS: Adults eligible for inclusion in a malaria treatment trial (n = 311) were randomized to receive information needed for informed consent using either a multimedia tool (intervention arm) or a standard procedure (control arm). A computerized, audio questionnaire was used to assess participants' comprehension of informed consent. This was done immediately after consent had been obtained (at day 0) and at subsequent follow-up visits (days 7, 14, 21 and 28). The acceptability and ease of use of the multimedia tool were assessed in focus groups. FINDINGS: On day 0, the median comprehension score in the intervention arm was 64% compared with 40% in the control arm (P = 0.042). The difference remained significant at all follow-up visits. Poorer comprehension was independently associated with female sex (odds ratio, OR: 0.29; 95% confidence interval, CI: 0.12-0.70) and residing in Jahaly rather than Basse province (OR: 0.33; 95% CI: 0.13-0.82). There was no significant independent association with educational level. The risk that a participant's comprehension score would drop to half of the initial value was lower in the intervention arm (hazard ratio 0.22, 95% CI: 0.16-0.31). Overall, 70% (42/60) of focus group participants from the intervention arm found the multimedia tool clear and easy to understand. CONCLUSION: A multimedia informed consent tool significantly improved comprehension and retention of consent information by research participants with low levels of literacy

Canadian Experiment for Soil Moisture in 2010 (CanEX-SM10): Overview and Preliminary Results

The Canadian Experiment for Soil Moisture in 2010 (CanEx-SM10) was carried out in Saskatchewan, Canada from 31 May to 16 June, 2010. Its main objective was to contribute to Soil Moisture and Ocean salinity (SMOS) mission validation and the pre-launch assessment of Soil Moisture and Active and Passive (SMAP) mission. During CanEx-SM10, SMOS data as well as other passive and active microwave measurements were collected by both airborne and satellite platforms. Ground-based measurements of soil (moisture, temperature, roughness, bulk density) and vegetation characteristics (Leaf Area Index, biomass, vegetation height) were conducted close in time to the airborne and satellite acquisitions. Besides, two ground-based in situ networks provided continuous measurements of meteorological conditions and soil moisture and soil temperature profiles. Two sites, each covering 33 km x 71 km (about two SMOS pixels) were selected in agricultural and boreal forested areas in order to provide contrasting soil and vegetation conditions. This paper describes the measurement strategy, provides an overview of the data sets and presents preliminary results. Over the agricultural area, the airborne L-band brightness temperatures matched up well with the SMOS data. The Radio frequency interference (RFI) observed in both SMOS and the airborne L-band radiometer data exhibited spatial and temporal variability and polarization dependency. The temporal evolution of SMOS soil moisture product matched that observed with the ground data, but the absolute soil moisture estimates did not meet the accuracy requirements (0.04 m3/m3) of the SMOS mission. AMSR-E soil moisture estimates are more closely correlated with measured soil moisture

Safety and Immunogenicity of ChAd63 and MVA ME-TRAP in West African Children and Infants.

Malaria remains a significant global health burden and a vaccine would make a substantial contribution to malaria control. Chimpanzee Adenovirus 63 Modified Vaccinia Ankara Multiple epitope thrombospondin adhesion protein (ME-TRAP) and vaccination has shown significant efficacy against malaria sporozoite challenge in malaria-naive European volunteers and against malaria infection in Kenyan adults. Infants are the target age group for malaria vaccination; however, no studies have yet assessed T-cell responses in children and infants. We enrolled 138 Gambian and Burkinabe children in four different age-groups: 2-6 years old in The Gambia; 5-17 months old in Burkina Faso; 5-12 months old, and also 10 weeks old, in The Gambia; and evaluated the safety and immunogenicity of Chimpanzee Adenovirus 63 Modified Vaccinia Ankara ME-TRAP heterologous prime-boost immunization. The vaccines were well tolerated in all age groups with no vaccine-related serious adverse events. T-cell responses to vaccination peaked 7 days after boosting with Modified Vaccinia Ankara, with T-cell responses highest in 10 week-old infants. Heterologous prime-boost immunization with Chimpanzee Adenovirus 63 and Modified Vaccinia Ankara ME-TRAP was well tolerated in infants and children, inducing strong T-cell responses. We identify an approach that induces potent T-cell responses in infants, which may be useful for preventing other infectious diseases requiring cellular immunity

Safety and Immunogenicity of Malaria Vectored Vaccines Given with Routine Expanded Program on Immunization Vaccines in Gambian Infants and Neonates: A Randomized Controlled Trial.

BACKGROUND: Heterologous prime-boost vaccination with chimpanzee adenovirus 63 (ChAd63) and modified vaccinia virus Ankara (MVA) encoding multiple epitope string thrombospondin-related adhesion protein (ME-TRAP) has shown acceptable safety and promising immunogenicity in African adult and pediatric populations. If licensed, this vaccine could be given to infants receiving routine childhood immunizations. We therefore evaluated responses to ChAd63 MVA ME-TRAP when co-administered with routine Expanded Program on Immunization (EPI) vaccines. METHODS: We enrolled 65 Gambian infants and neonates, aged 16, 8, or 1 week at first vaccination and randomized them to receive either ME-TRAP and EPI vaccines or EPI vaccines only. Safety was assessed by the description of vaccine-related adverse events (AEs). Immunogenicity was evaluated using IFNγ enzyme-linked immunospot, whole-blood flow cytometry, and anti-TRAP IgG ELISA. Serology was performed to confirm all infants achieved protective titers to EPI vaccines. RESULTS: The vaccines were well tolerated in all age groups with no vaccine-related serious AEs. High-level TRAP-specific IgG and T cell responses were generated after boosting with MVA. CD8+ T cell responses, previously found to correlate with protection, were induced in all groups. Antibody responses to EPI vaccines were not altered significantly. CONCLUSION: Malaria vectored prime-boost vaccines co-administered with routine childhood immunizations were well tolerated. Potent humoral and cellular immunity induced by ChAd63 MVA ME-TRAP did not reduce the immunogenicity of co-administered EPI vaccines, supporting further evaluation of this regimen in infant populations. CLINICAL TRIAL REGISTRATION: The clinical trial was registered on http://Clinicaltrials.gov (NCT02083887) and the Pan-African Clinical Trials Registry (PACTR201402000749217)

Viral Vector Malaria Vaccines Induce High-Level T Cell and Antibody Responses in West African Children and Infants.

Heterologous prime-boosting with viral vectors encoding the pre-erythrocytic antigen thrombospondin-related adhesion protein fused to a multiple epitope string (ME-TRAP) induces CD8+ T cell-mediated immunity to malaria sporozoite challenge in European malaria-naive and Kenyan semi-immune adults. This approach has yet to be evaluated in children and infants. We assessed this vaccine strategy among 138 Gambian and Burkinabe children in four cohorts: 2- to 6-year olds in The Gambia, 5- to 17-month-olds in Burkina Faso, and 5- to 12-month-olds and 10-week-olds in The Gambia. We assessed induction of cellular immunity, taking into account the distinctive hematological status of young infants, and characterized the antibody response to vaccination. T cell responses peaked 7 days after boosting with modified vaccinia virus Ankara (MVA), with highest responses in infants aged 10 weeks at priming. Incorporating lymphocyte count into the calculation of T cell responses facilitated a more physiologically relevant comparison of cellular immunity across different age groups. Both CD8+ and CD4+ T cells secreted cytokines. Induced antibodies were up to 20-fold higher in all groups compared with Gambian and United Kingdom (UK) adults, with comparable or higher avidity. This immunization regimen elicited strong immune responses, particularly in young infants, supporting future evaluation of efficacy in this key target age group for a malaria vaccine

Prevention of the Recurrence of Anaemia in Gambian Children Following Discharge from Hospital

BACKGROUND: In malaria endemic countries, children who have experienced an episode of severe anaemia are at increased risk of a recurrence of anaemia. There is a need to find ways of protecting these at risk children from malaria and chemoprevention offers a potential way of achieving this objective. METHODS: During the 2003 and 2004 malaria transmission seasons, 1200 Gambian children with moderate or severe anaemia (Hb concentration <7 g/dL) were randomised to receive either monthly sulfadoxine-pyrimethamine (SP) or placebo until the end of the malaria transmission season in which they were enrolled, in a double-blind trial. All study subjects were treated with oral iron for 28 days and morbidity was monitored through surveillance at health centres. The primary endpoint was the proportion of children with moderate or severe anaemia at the end of the transmission season. Secondary endpoints included the incidence of clinical episodes of malaria during the surveillance period, outpatient attendances, the prevalence of parasitaemia and splenomegaly, nutritional status at the end of the malaria transmission season and compliance with the treatment regimen. RESULTS: The proportions of children with a Hb concentration of <7 g/dL at the end of the malaria transmission season were similar in the two study groups, 14/464 (3.0%) in children who received at least one dose of SP and 16/471 (3.4%) in those who received placebo, prevalence ratio 0.89 (0.44,1.8) P = 0.742. The protective efficacy of SP against episodes of clinical malaria was 53% (95% CI 37%, 65%). Treatment with SP was safe and well tolerated; no serious adverse events related to SP administration were observed. Mortality following discharge from hospital was low among children who received SP or placebo (6 in the SP group and 9 in the placebo group respectively). CONCLUSIONS: Intermittent treatment with SP did not reduce the proportion of previously anaemic children with moderate or severe anaemia at the end of the malaria season, although it prevented malaria. The combination of appropriate antimalarial treatment plus one month of iron supplementation and good access to healthcare during follow-up proved effective in restoring haemoglobin to an acceptable level in the Gambian setting. TRIAL REGISTRATION: ClinicalTrials.gov NCT00131716